According to Hindu lunar calendar, two per month, twenty-four Ekadasi's will come.
According Candraman per every three years extra month will come. Twenty-six Ekadasi's fall overboard. Ekadasi is the meaning of eleven. In Padmapurana's Ekadasi is said about the designation.
Explained in a number of stories about the myths associated with Ekadasi mystic Srihari. Srihari has created Ekadasi to save people from their troubles, people who does this Ekadasi Vrata with devotion and concentration they will get emancipation (Vimukti), after death they will go to Vikuntam (where lord Vishnu lives) noted in Padmapurana.
Ekadasi day people will do fasting and worship to Lord Srihari. On next day early in the morning, Naivedya Thambulalu submitted to Srihari and then they will sit for dine.
Among the reasons for the strike was that Dwadashi fasting, according to Vishnu's blessing, the baby hidden in the rice, Sweat point which is fell down and it became monster and asked for residence to Brahma, 'who ever eats on Ekadasi day live in their rice' he said.
Two giants of the day, they are filled with rice, insects became so involved in stomach illness, our myths are revealed indirect warning. This is what is also known as Indaraikadasi.
The king Indrasena is in hell so his son did Ekadasi vrata on this day. So his father was releived from hell and sent him to heaven.